The extracellular matrix (ECM) undergoes extensive architectural remodeling during tumor progression, generating nanoscale alignment cues that profoundly influence behaviors of immune cells. However, whether ECM nanoarchitecture directly programs their immune secretory functions remains poorly defined. Here, we develop a magnetically switchable hydrogel that enables reversible, on-demand modulation of nanoscale ligand alignment without altering bulk stiffness or composition. Using this platform, we uncover a mechanotransduction pathway in tumor-associated macrophages (TAMs) whereby matrix nanoalignment enhances integrin β1-dependent mechanosensing and transient receptor potential cation channel subfamily V member 2 (TRPV2)-dependent Ca2+ signaling, thereby promoting phosphoinositide 3-kinase (PI3K)–Ras-related protein 11a (Rab11a)-associated small extracellular vesicle (sEV) release by approximately tenfold. Beyond increasing vesicle output, PI3K–mechanistic target of rapamycin complex 2-associated signaling altered the particle-normalized cargo profile of sEVs, with preferential enrichment of immunoregulatory molecules, including M2-promoting cytokines and miR-181a-5p. These sEVs reprogram macrophages toward an immunosuppressive M2-like phenotype, suppress cytotoxic CD8+ T-cell infiltration, and accelerate melanoma progression in vivo. Importantly, selective disruption of the TRPV2–Rab11a axis or pharmacological attenuation of ECM remodeling restores antitumor immunity and restricts tumor growth. Together, our findings demonstrate that ECM nanoarchitecture is sufficient to regulate macrophage sEV programming in a defined matrix environment and identify TRPV2-associated mechanotransduction as a potential therapeutic vulnerability in matrix-remodeled tumors.
To enhance proactive hydrogen safety control capabilities, the comprehensive scenario spanning hydrogen leakage diffusion, water mist activation, and ignition explosion has constructed based on the ship engine room. The study systematically investigated the influence mechanisms of water spray location, flow rate, and activation time on hydrogen diffusion behavior and explosion characteristics, followed by quantitative risk assessment. Results indicate that adopting a water mist deployment strategy near the leakage source and aligned with buoyancy direction can reduce the hydrogen hazardous area from 659.3 m3 to 220.6 m3, with overpressure peak, temperature, and shock wave velocity decreasing by 8.5 % to 9.1 %. The water mist flow exhibits a critical threshold effect. When the flow rate is 7.0 L/min, the hazardous area further decreases to 94.9 m3, with the aforementioned parameters dropping by 12.1 % - 22.2 %, demonstrating significant explosion suppression. At a flow rate of 3.0 L/min, the intensified disturbance flow field exacerbates hydrogen accumulation and explosion intensity. Early activation of water mist achieves "preventive suppression", such as activation 10 s after leakage can reduce the explosion overpressure and temperature from 160.1 kPa and 1807 K to 89.2 kPa and 1173.7 K, and significantly shorten the risk range and duration of high-temperature and high-pressure areas. The research results can provide the theoretical basis and data support for the design of water mist explosion suppression parameters and hydrogen safety protection in confined spaces.
Hydrogen leakage in tightly enclosed and geometrically complex marine engine rooms poses a critical safety challenge for hydrogen-fueled ships, where combustible mixtures may persist near potential ignition sources. Existing studies have mainly focused on concentration distribution, ventilation performance, or sensor response, while the coupling between flammable-cloud evolution and local exposure near high-temperature components remains insufficiently quantified. In this study, a three-dimensional transient computational fluid dynamics (CFD) model of a marine engine room with the main internal equipment retained was developed. A small-hole pipeline leakage source was introduced using a compressible-gas source-term model, and the release, source-isolation, and ventilation-removal stages were analyzed. The assessment combined the flammable-cloud volume (Vflam), the duration of exposure above the lower flammability limit (LFL), and the first arrival time to the LFL near potential ignition sources to distinguish compartment-scale cloud development from local hot-surface exposure. The results show that leakage height produced a non-monotonic response governed by local equipment blockage, with an intermediate-height leakage case generating the largest peak Vflam among the height cases. Higher initial pipeline pressure and ambient temperature enlarged the flammable cloud through increased release intensity and thermal expansion, respectively, whereas stronger ventilation reduced the global cloud volume but did not uniformly suppress local above-LFL exposure. The integrated comparison further shows that the largest flammable cloud does not necessarily correspond to the earliest local LFL arrival. These findings provide a basis for cloud-scale ventilation control, targeted monitoring, and local protection of high-temperature regions in hydrogen-fueled marine engine rooms.
Natural ice is a sustainable material for cold-region construction but limited by its brittleness and low strength. This study proposes ice-filled square steel tubular (IFSST) columns to enhance the mechanical performance of ice through external confinement, with an emphasis on thin-walled steel tubes to balance economy and composite efficiency. Axial compression tests including plain and sawdust-reinforced ice-filled tubes with width-to-thickness (B/t) ratios of 50, 75, and 100 were conducted. The results revealed that the composite columns failed by steel tube outward buckling with ductile deformation. The strength index of IFSST columns ranged from 1.00 to 1.54 and increased with B/t ratio, indicating a pronounced composite effect. Sawdust reinforcement significantly enhanced ductility with ductility indices of 5.8–14.7, far exceeding those of concrete-filled steel tubes. Stress analysis revealed that increasing B/t ratio reduced steel tube's peak axial stress but increased its ultimate hoop stress. A design-oriented model capturing the key mechanical behavior of each component was proposed, with predicted load-strain curves and ultimate bearing capacities showing good agreement with available experimental results. This study demonstrated that thin-walled steel tubes could work synergistically with inner ice, providing a viable pathway for utilizing ice as a structural material.
